Lamp socket with clamp member



Sept. 14, 1965 H. w. SCHICK ETAL LAMP SOCKET WITH CLAMP MEMBER OriginalFiled July 24, 1962 E m w W JOHN W. PETERSON HENRY W. SCHICK.

ATTORNEYS United States Patent 3,206,712 LAME SG'CKE'I WlTH CLAMP MEMBERHenry W. Schick, Mastic Beach, and John W. Peterson, Douglaston, N.Y.,asslgnors to Gilbert Manufacturing Company, Inca, Long lsiand City,N.Y., a corporation of New York Original application July 24, 1962, Ser.No. 212,tl35, now Patent No. 3,151,926, dated Oct. 6, 1964. Divided andthis application Aug. 20, 1964, Ser. No. 395,353 7 Claims. (Cl. 339-99)This application is a division of our copending application Serial No.212,085, filed July 24, 1962, entitled Lamp Socket, which is assigned tothe same assignee and is now United States Letters Patent 3,151,926issued on October 6, 1964.

This invention relates to lamp sockets which are adapted to be mountedalong the length of an electrical conductor cord at any point thereofand more particularly to lamp socket assembly of the pin-tap type inwhich connection is made between the electrical contact elements of thesocket and the conductor cord by piercing the wires of the conductorcord.

The present invention is directed to a relatively simple lamp socketwhich may be removably secured to and mounted at any point along aconductor cord which supplies the current for the lamp bulb in thesocket. In accordance with the invention, the lamp socket comprises ashell or husk of plastic material having internal threads to receive andhold the base of the lamp bulb. Two grooves are formed on opposite wallsof the shell for receiving and holding respective blade-type electriccontact members. One end of each contact member is formed with a prongfor piercing through the insulation of the conductor cord to makeelectrical contact with a conductor wire and each contact member isalsoformed with a tab or tongue to make contact with one of theelectrical contact points on the lamp bulb base. In this way a currentpath is provided from the conduct-or cord to the hub. The bottom of thesocket shell is formed with a channel to hold the conductor cord and awedge piece is provided to be placed in the channel on top of theconductor cord to hold it within the channel. In order to secure thewedge piece to the shell and to force the prongs of the contact membersto pierce through the conductor wires an L-shaped clamp is provided. Onearm of the clamp is formed with two portions which engage the body onopposite sides of the wedge piece. The clamp is made of suitable sizeand of a suitable material so that a tight fit is achieved and enoughpressure is applied to the wedge piece to force it into the channelthereby causing the prongs to pierce the conductor wire. The clamp isalso formed with a clip which allows the complete socket assembly andbulb to be mounted at a desired location, for example, on the branch ofat Christmas tree.

The above described socket has several advantages. First of all, it isrelatively simple in construction and assembly and needs no soldering orother type fastening arrangement to make contact between the socketcontact members and the wires of the conductor cord. Further, thepin-tap assembly of the electrical contact blades makes the socketattachable at any point along the conductor cord; also, the L-shapedclamp is preferably made of tempered spring steel and its relativelysimple shape uses a minimum amount of material and provides for easymanufacture and assembly. The use of spring steel for the clamp alsogives the clip formed thereon better holding properties and increasedlife.

In a preferred form of the invention, the wedge piece is of pyramidalshape so that when it is laid in the channel against the wires the wiresfollow the contour of the 512%,712 Patented Sept. 14%, 1965 wedge pieceand strain relief is provided by virtue of the conductor wires runningover the highest portion of the pyramid. This is a relatively simple wayof providing strain relief without the use of any additional parts.

It is therefore an object of this invention to provide a lamp socket ofthe pin-tap type wherein the clamp which secures the conductor holdingpiece is L-shaped and is provided with a clip to secure the socketassembly to a support.

A further object of the invention is to provide a lamp socket havingblade type contact members which pierce through the insulation of aconductor cord, the conductor cord being held in a channel in the socketand pressed into electrical contact with the contact members by aconductor holding wedge piece.

Yet another object of the invention is to provide a lamp socket of thepin-tap type in which the conductor cord is held in a channel in thesocket and pressed into electrical contact with the prong of bladecontact members by a wedge piece with is held within the channel by anL- shaped clamp member.

Still another object of the invention is to provide a lamp socket inwhich the wedge piece holding the wires within the socket is shaped toprovide strain relief.

Other objects and advantages of the present invention will become moreapparent upon reference to the following specification and annexeddrawings in which:

FIGURE 1 is a side elevational view of the lamp socket assembly, withthe lamp socket shown partially broken away in order to illustratecertain features of the invention;

FIGURE 2 is a front elevational view of the lampsocket taken partiallyin section along lines 2-2, FIG- URE 1 and partially broken away;

FIGURE 3 is a perspective View of the bottom of the lamp socket showinga portion of the conductor cord running therethrough;

FIGURE 4 is a perspective view of the wedge piece;

FIGURE 5 is a front elevational view of one of the blade contactmembers;

FIGURE 6 is a perspective view of a clamping memher for holding thewedge piece within the socket shell without fastening over the top rimof the socket; and

FIGURE 7 is a perspective view of the clamping member and a portion ofthe bottom of the lamp socket.

Referring to FIGURES 1-7, the lamp socket is formed by a substantiallyhollow shell or husk 10, which has an opening 11 at the top thereof, endwalls 12 and 13, and side walls 14 and 15. The top opening 11communicates with a cavity 16 which extends substantially the entireheight of the shell. The shell 1tl, as well as the other non-metallicparts of the socket, is preferably made of a plastic insulating materialsuch as Bakelite or of another plastic material which has the necessarystrength. The top opening 11 of the shell is flared out to accommodatethe base 18 and the bottom portion of the glass envelope of a bulb 17which is screwed into threads 19 formed on the side walls 14 and 15. Thebulb 16 may be of any desired shape, type, and/or wattage and the sizeof the shell 10 and threads 19 may be varied to accept different bulbs.

The end walls 12 and 13 of the shell are respectively formed withchannels or grooves 21 (only one of which is shown in FIGURE 2) to holda respective blade contact member 23 or 24. The grooves 21 are made of asuitable size so that the blade contact members 23 and 24 are tightlyheld therein when they are placed in the grooves. As shown in FIGURE 6,each blade contact member is formed with a downwardly extending sharppointed prong 25 at the bottom end thereof which is of a size to makecontact with one of the wires 26 or 27 of a two conductor cord 28. Theblade contact members 23 and 24 are formed and located within the shellso that the prong of one is adjacent the side wall 14 and the prong ofthe other adjacent the side wall 15. Therefore, each prong will makecontact with only one of the wires 26 or 27. Any suitably shaped bladecontact member may be utilized so long as has the sharp pointed prong topierce the current carrying wire and can be held within the socket body.

Blade contact member 23 has a tongue which extends into the shell cavity16 to make electrical contact with the bottom contact point 31 of thelamp bulb base 18 when the bulb is screwed substantially all the waydown on the threads 19. The other blade contact member 24 has a bent-outtab portion 32 which makes electrical contact with the metallic threadedportion 33 on the side of the bulb base. In this manner an electriccircuit is established to provide current to the lamp filament throughthe two wires 26 and 27 of the conductor, blade contact members 23 and24 and their respective tongue and tab 30 and 32, and the two contactpoints 31 and 33 on the lamp bulb base.

The socket shell 10 also has a bottom wall 36 which is formed with alongitudinal channel 37 therein running between the end walls 12 and 13.The channel 37 extends part way up into the end walls 12 and 13 whichhave cut out sections 39 (FIGURE 1) so that the conductor cord 28 may bereadily placed in the channel 37 and held within the socket. The prong25 of each blade contact member 23 and 24 extends part way down into thechannel 37 to a point opposite the openings 39 in end walls 12 and 13and above the bottom wall 36 of the shell. As described previously, theblade contact members are lo cated in grooves 21 in the end walls.

A wedge piece 40 is provided to fit Within the channel 37 and to holdthe conductor cord within the shell. The wedge piece holds the conductorcord 28 within the channel 37 and when it is clamped, exerts pressure onthe wires 26 and 27 so that the prongs 25 of the blade contact memberspierce through the wires. Wedge piece 40 is generally pyramidal in shapewith a high point 41 at the center thereof and sloping surfaces 42tapering off from the high point along the longer dimension of thepiece. The center portion of the wedge piece is also cut out on bothsides and has sloping surfaces 44 which run from the top of the piece.The surfaces 44 extend down to the bottom of the wedge piece but do notreach the sides 45 thereof so that openings or notches 43, which areshown in FIGURES 3 and 4, are provided on the piece. These notches maynot be needed. Each end of the piece 40 is also provided with twonotches 46 which allow the piece 40 to fit over the abutting pieces 47of the end walls 12 and 13. It can be seen that the piece 40 issymmetrical so that it can be placed either way in the channel 37 withthe high point 41 facing in toward the center of cavity 16. Of course,any suitable shape wedge piece may be used.

A clamp 50 is used to hold the wedge piece 40 to the socket and to exertpressure on the piece so that the prongs 25 of the blade contacts willpierce through the wires of the conductor cord. The clamp 50 is formedof tempered spring steel or some other suitable material and ispreferably generally L-shaped with a long arm 52 and a short arm 53. Thecenter portion of the longer arm of the L-shaped clamp may be punchedout and bent to form a clip 54 which is used to mount the socket andbulb on a desired support or else this clip may be formed as a bent overextension of the long arm 52 of the clamp, as shown best in FIGURES 3and 6.

In assembling the complete lamp socket, the conductor cord 28 is firstlaid into the channel 37 into which the prongs 25 extend near the endwalls 12 and 13. The wedge piece 40 is next placed on the shorter arm 53of the L-shaped clamp. The wedge piece is next forced into position sothat its bottom is substantially flush with the bottom 36 of the socketby applying pressure to the short arm 53 of the clamp so that the wedgepiece 40 is forced into the channel and sufficient pressure is exertedto force wires 26 and 27 up onto the prongs 25. The prongs piercethrough the insulation surrounding the wires 26 and 27 so that the bladecontacts make elec trical contact with the inner conductors of thewires. The short arm 53 is fastened to the shell 10 in a mannerdescribed in greater detail below. Of course, the assembly procedure maybe changed.

It should be noted that both of the wires in the channel are forced tofollow the general contour of the wedge-shaped piece 40 in the channelso that at the center of the channel the wires run over the high point41. The sloping surfaces 42 and the high point 41 of the wedge pieceprovide strain relief for the wires and prevent them from beingseparated from the blade contact members when a pull is exerted on thewires.

FIGURES 6 and '7 show details of a clamp for fastening the wedge piece40 without the need of fastening the clamp 50 over the top rim of thesocket body. The clamp is of one piece construction and its short arm 53is bent and is stamped out to have two upstanding pieces 65 and 71 theformer of which is generally T-shaped. The bottom of the socket body forthis clamp has formed on the interior of one side wall 14 adjacentbottom wall 36 a notch 62 and two sloping bosses 63 and 64'. A notch 62and a single sloping boss 70 are formed on the interior of the oppositeside wall 15 adjacent bottom wall 36. Therefore, in assembling the clampto the socket the T- shaped piece 65 is fastened over the two bosses 63and 64 on one side wall and the cutout piece 71 is fastened over thesingle boss 70 on the other side wall with the wedge piece 40 beingbetween the two upstanding pieces 65 and 71. The two pieces 65 and 71fit within the notches 43 of the wedge piece 40 and/or the notches 62 ofthe side walls. The clamp of FIGURES l-7 does not need a hook to fastenover the top rim of the socket since positive clamping of the wedgepiece 40 is provided by the pieces 65 and 71 in cooperation with thebosses 63-64 and 70. A similar arrangement without the hook 52 on theclamp can be formed by providing slots on each side of the channel 37and by punching out barbed legs from the bottom piece 53 of the clampingmember 50 to fit in these slots.

While a preferred embodiment of the invention has been described above,it will be understood that this is illustrative only, and the inventionis limited solely by the appended claims.

What is claimed is:

1. A lamp socket assembly comprising a substantially hollow shell havinga bottom wall and an opening in the top thereof to receive a lamp bulb,a pair of blade type contact members each having a prong portion at thebottom thereof, said shell having means to receive and hold the bladecontact members, a channel in the bottom of said shell through a portionof said bottom wall adapted to receive a pair of current carrying wires,the bottom wall of said shell on one side of said channel formed with anotch portion and a single projecting boss and the bottom wall on theother side of the channel formed with a notch portion and a pair ofrojecting bosses, a wedge piece formed with openings therein to fit insaid channel and adapted to hold the wires therein and press a wireagainst the prong of a respective blade member, and an L-shaped clampfor holding said wedge piece in said channel, said clamp formed with; afirst piece having a cutout portion to extend into one of the Wedgepiece openings and to fasten onto the single projecting boss, 21 secondpiece to engage said wedge piece, and a third piece which has a T-shapedportion to extend into the other wedge piece opening and fasten onto thepair of projecting bosses.

2. A lamp socket assembly as set forth in claim 1 wherein said clamp isformed with a clip member adapted to hold said socket assembly to asupport.

3. A lamp socket assembly as set forth in claim 2 wherein said wedgepiece is formed with oppositely sloping surfaces thereon within thechannel to provide strain relief for said wires.

4. A lamp socket assembly comprising:

a substantially hollow shell member having a bottom wall and an openingin the top wall thereof adapted to receive a lamp bulb, the bottom ofsaid shell formed with a channel adapted to receive a pair of currentcarrying Wires,

at least one abutment projecting from the interior of each of the sideWalls of said shell member toward the interior of said shell,

a pair of contact members each having a portion thereon adapted to makeelectrical contact with a respective current carrying Wire, said shellmember having means to hold said contact members,

a wedge piece to fit in said channel and adapted to hold the currentcarrying Wires therein; said wedge piece and said bottom wall defining apassage into the interior of said shell member on each side of saidwedge piece,

and a clamp member having an arm formed with two upstanding portions,the Wedge piece located between said upstanding portions of said arm andsaid portions extending into said shell interior through said passagesto engage said abutments to thereby hold the Wedge piece to the shellmember.

5. A lamp socket as set forth in claim 4 wherein said side walls of saidchannel are each formed. with a recess in Which a corresponding abutmentis located.

6. A lamp socket as set forth in claim 4 wherein the clamp member hasanother arm and said member is generally L-shaped with the other armextending generally along the outside of the shell.

7. A lamp socket as set forth in claim 6 wherein said other arm isprovided with a spring clip member thereon.

References Cited by the Examiner UNITED STATES PATENTS 2,636,069 4/53Gilbert 33999 2,938,189 5/60 Keeler et al. 339-99 JOSEPH D. SEERS,Primary Examiner.

4. A LAMP SOCKET ASSEMBLY COMPRISING: A SUBSTANTIALLY HOLLOW SHELLMEMBER HAVING A BOTTOM WALL AND AN OPENING IN THE TOP WALL THEREOFADAPTED TO RECEIVE A LAMP BULB, THE BOTTOM OF SAID SHELL FORMED WITH ACHANNEL ADAPTED TO RECEIVE A PAIR OF CURRENT CARRYING WIRES, AT LEASTONE ABUTMENT PROJECTING FROM THE INTERIOR OF EACH OF THE SIDE WALLS OFSAID SHELL MEMBER TOWARD THE INTERIOR OF SAID SHELL, A PAIR OF MEMBERSEACH HAVING A PORTION THEREON ADAPTED TO MAKE ELECTRICAL CONTACT WITH ARESPECTIVE CURRENT CARRYING WIRE, SAID SHELL MEMBER HAVING MEANS TO HOLDSAID CONTACT MEMBERS, A WEDGE PIECE TO FIT IN SAID CHANNEL AND ADAPTEDTO HOLD THE CURRENT CARRYING WIRES THERIN; SAID WEDGE PIECE AND SAIDBOTTOM WALL DEFINING A PASSAGE INTO THE INTERIOR OF SAID SHELL MEMBER ONEACH SIDE OF SAID WEDGE PIECE, AND A CLAMP MEMBER HAVING AN ARM FORMEDWITH TWO UPSTANDING PORTINS, THE WEDGE PIECE LOCATED BETWEEN SAIDUPSTANDING PORTIONS OF SAID ARM AND SAID PORTIONS EXTENDING INTO SAIDSHELL INTERIOR THROUGH SAID PASSAGES TO ENGAGE SAID ABUTMENTS TO THEREBYHOLD THE WEDGE PIECE TO THE SHELL MEMBER.